Ferroelectric Hafnium Oxide Material Enhanced Reliability

该项目的主要目标是了解电容器结构中介电材料和基于HfO2或ZrO2的铁电层之间的相互作用。在该双层结构堆叠中，在铁电偶极子和电荷(例如，电子、空穴、带电氧空位)之间发生了强烈的相互作用。由于从铁电电容、铁电场效应晶体管和铁电隧道结到负电容FET和红外传感器等各种半导体器件中存在不同的介电和铁电层厚度比，因此不同器件的影响可能会有所不同，但基本特性保持不变。到目前为止，对缺陷和电荷的影响的详细了解是有限的，迫切需要进一步的研究来使HfO2基铁电材料在广泛的应用中引入成为可能。为了了解掺杂价态对铁电电容器可靠性(记忆窗口、漏电流、唤醒行为、保持性、疲劳性和耐久性)的影响，用不同价态的原子掺杂HfO2和ZrO2基铁电层。此外，还将研究铁电/电介质层厚度比以及电极材料对电容器膜堆的影响，以减少捕获行为并获得更好的性能。为了实现这些结果，将通过不同的表征技术来研究活性介质的电子结构和原子结构，这些技术将通过从头计算的实验发光和电荷输运实验来补充和加强。所获得的结果可以获得铁电性能退化行为的详细微观模型，以便为铁电器件提供实用建议。该项目的总体目标是在可靠性、性能、环境兼容性、CMOS兼容性、基本材料的可用性方面对这种新的无铅铁电材料进行优化。

The main objective of the project is to understand the interplay between a dielectric and a HfO2- or ZrO2-based ferroelectric layer within a capacitor structure. Within this bi-layer structure stack a strong interaction between the ferroelectric dipoles and charges (e.g. electrons, holes, charged oxygen vacancies) occur. Since different thickness ratio of dielectric and ferroelectric layer are present in a wide range of semiconductor devices from ferroelectric capacitor via ferroelectric field effect transistors and ferroelectric tunnel junctions to negative capacitance FETs and infrared sensors, effects might change from one device to another, but basic characteristics remain similar. So far, a detailed understanding of the effects of defects and charges is limited, and further studies are urgently needed to make the introduction of HfO2 based ferroelectric materials in a wide range of applications possible. HfO2- and ZrO2-based ferroelectric layers are doped by atoms with different valence to understand the impact of dopant valence on the ferroelectric capacitor reliability (memory window, leakage, wake-up behavior, retention, fatigue, and endurance). Furthermore, the impact of the thickness ratio of ferroelectric/dielectric layers as well as electrode materials will be studied on the capacitor film stacks to reduce trapping behavior and get better performance. To achieve these results, the electronic and atomic structure of active mediums will be studied by different characterization techniques which will be supplemented and strengthened by experimental luminescence and charge transport experiments with ab initio simulations. Obtained results allow to obtain a detailed microscopic model for the degradation behavior of ferroelectric properties in order to develop practical recommendations for ferroelectric devices. The overall goal of the project is an optimization of this new lead-free ferroelectric material with respect to reliability, performance, environmental compatibility, CMOS compatibility, availability of the basic material.